User talk:P.wormer

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Welcome!

Hello, P.wormer, and welcome to Wikipedia! Thank you for your contributions. I hope you like the place and decide to stay. Here are some pages that you might find helpful:

I hope you enjoy editing here and being a Wikipedian! Please sign your name on talk pages using four tildes (~~~~); this will automatically produce your name and the date. If you need help, check out Wikipedia:Questions, ask me on my talk page, or place {{helpme}} on your talk page and someone will show up shortly to answer your questions. Again, welcome! Hu 11:25, 2 November 2006 (UTC)

[edit] Creating stubs

Stubs are good, but please create them with basic formatting (bolding of the title in the first sentence), and with a good category or stub tag or two. Also, please place text for each paragraph on a single line with out explicit line breaks, though this is only a courtesy, not critical. See the changes I made on Wigner D-matrix. Hu 11:26, 2 November 2006 (UTC)

[edit] Rigid rotor

What my original concern was was that you might have been relying on contents of the quantum mechanics article to write your new contribution, but that was probably just a poor choice of words.

The only thing that I have really checked is that you have included sources. Provided that you actually have seen copies of the documents you quote and, together, they account for the whole contents of your additions, that should be OK. However, they look like they may be the original research papers. It's better to use a subsequent text book, because:

information in text books is usually generally accepted material, whereas an original research paper may actually be rejected by most of the research community;

text books may be easier for other people to access, to check that the article really does match its sources.

-- David Woolley 23:23, 26 November 2006 (UTC)

[edit] Great orthogonality theorem

Thank you for your contributions. I could never have produced that much information about GOT. I would like to point out that I am unsure how to make the GOT page show up as an option if you search for "GOT". If you figure out how to do this, please let me know.

Cheers, Piercen 15:48, 4 December 2006 (UTC)

Just came by and saw this thread. You can do this: [1] - or, if that page didn't exist, you can create a redirect by typing #REDIRECT [[Great orthogonality theorem]] in the GOT page. More information at Wikipedia:Redirect. --HappyCamper 14:00, 8 December 2006 (UTC)

[edit] Hello!

Regular Wikipedian here - just thought I might drop by and say how wonderful your additions to rigid rotor are! Anyway, I wonder if you have more materials you could add to vibronic coupling? On another tangent, you might be interested to check out Wikipedia:WikiProject Chemistry. There are a few physical and organic chemists there. Feel free to let me know if you have any questions. Cheers, HappyCamper 19:04, 6 December 2006 (UTC)

Thanks for your note on my talk page. A few housekeeping things. I've noticed that no Wikipedian has told you about the goodies yet. Just in case:

There is a little plus sign at the top of talk pages which you can use to start a new discussion thread. It automatically creates a new section. The four dashes ---- does not create a new editing section so it's not used often. However, you'll see this used, say, in very long threads. You'll also see this if people are trying to design the visual layout of pages and sections.
When you edit, there are a number of blue coloured buttons at the top of the edit window itself. They are shortcuts to introduce Wiki syntax into the text. Very useful if you want to design tables and organize images. Sometimes, people use these to display equations - see Fourier transform for an example.
There should be a few tabs at the top of your screen, like "move" and "history" which you might like to experiment with. There is also a "special pages" link to your left, inside a section labeled the toolbox.

Now, about Born-Oppenheimer - we had an article for a while, but we removed it because we couldn't figure out what was the best way to present the material. Check the history of that article, and also the talk page. Feel free to start from scratch, or edit directly from an older copy of the article. To do this, you can click on an older copy, and just choose the one you'd like to edit from. I'll contact User:Martin Hedegaard, but I'm sure it's alright if you just start editing as you see fit. --HappyCamper 13:45, 8 December 2006 (UTC)

On another note, I assume you have a copy of that 1927 paper in the Annalen der Physik that Born and Oppenheimer wrote? It actually surprised me quite a bit that the modern interpretation given in textbooks and such is quite different from how they presented it almost 80 years ago. --HappyCamper 13:53, 8 December 2006 (UTC)

Hi, just regarding the Born-Oppenheimer approximation, if you want just go ahead and edit, I only did the merging of articles because the existing articles on the subject was very bad. If you in any way can improve the material on the subject by splitting the article again then go ahead. Martin Hedegaard 15:43, 8 December 2006 (UTC)

Thanks to the link to the translated BO paper. Very handy. As for the 1982 Mead-Truhlar paper, it was just sitting on my desk! --HappyCamper 02:25, 9 December 2006 (UTC)

[edit] Breaks

Hi Paul, I've noticed that some edits you make to Wikipedia seem to have contain extra line breaks. I haven't seen this before on Wikipedia. May I ask which browser are you using? --HappyCamper 12:07, 13 January 2007 (UTC)

Hi HC, Firefox 1.5.09. You probably know that line breaks don't take space, at most 2 bytes: ascii 10,13. Under Unix one byte: ascii 10. --P.wormer 15:07, 13 January 2007 (UTC)

[edit] Battle of Mookerheyde

Sorry, I don't have a source for that information; that edit was a procedural merge from the Mookerhei article. --Alan Au 17:10, 26 January 2007 (UTC)

[edit] Stark effect diagram

I have responded to your comments regarding the energy level diagram in Stark effect, please see Talk:Stark_effect#Drawing.--DJIndica 01:05, 25 February 2007 (UTC)

Thank you for your attention to this issue, it seems I was careless with the creation of the diagram and only 7 sublevels were included for each n-level. There should be n-1 sublevels -n+2, -n+4,... n-4, n-2. I have uploaded a new version, see my sandbox for a proposed scheme for displaying it in Stark effect. I would appreciate your comments/suggestions.--DJIndica 20:09, 1 March 2007 (UTC)

I have added the new diagram with an updated caption. I am not totally happy with the caption, I may make a new diagram which includes the magnetic quantum number. It may be worth including in the article a discussion of the quantum number describing the Stark states, even though it is slightly confusing to have a quantum number labelled as (n1 - n2) which is derived from a solution to the Schrodinger equation in parabolic coordinates. —The preceding unsigned comment was added by DJIndica (talk • contribs) 22:59, 4 March 2007 (UTC).

[edit] Molecular vibration

Thanks for the link. I had missed this article. It probably needs more links to it. Just one small point: expressing normal coordinates in terms of Cartesian coordinates is of very little value (except perhaps for creating animations!?), particularly as the force-field is usually expressed in terms of internal coordinates.Petergans 07:56, 27 March 2007 (UTC)

Hi Petergans, that used to be the case, but not any longer: modern ab initio programs compute the force constant matrix (Hessian of the PES) in terms of mass weighted Cartesians. Diagonalization of this matrix gives the normal coordinates in terms of Cartesians (plus 6 eigenvectors of zero eigenvalue, because in this approach the molecule is neither rotating nor translating). --P.wormer 00:22, 28 March 2007 (UTC)
Good point. To follow it up, I searched Wikipedia for "force field" and found nothing relevant to vibrational spectroscopy! There is a gap here which I don't feel qualified to fill, especially in relating Ab Initio results to VFF, UBF etc.Petergans 21:03, 28 March 2007 (UTC)
Here I am in in not so sunny Italy, working in the dept. of chemistry in Florence where, incidentally, Califano still makes occasional appearances. I too am retired, for Leeds University (inorganic chemistry), but am still active in the field of stability constant determination.

I thought about our discussions on the flight over here and have come to the conclusion that it would be better to be more rigorous. Omit the issue of coordinates from the introduction altogether and add a sub-section on Cartesian coordinates where the issue of separation of vibration and rotation can be treated properly. This would also be a good place to mention the ab initio calculations, but I need some help on that subject, never having done it myself. Your suggestions will be welcome

Hallo Petergans, you may want to have a look at Molecular Hamiltonian#Harmonic nuclear motion Hamiltonian and GF method#Normal coordinates in terms of Cartesian displacement coordinates. --P.wormer 14:28, 30 March 2007 (UTC) (who is in sunny California)

[edit] Follow-up

Hi Paul. That IP address has been in trouble before. The better reason for making that edit is to "skip over a redirect", which is what I have indicated now. Skipping over redirects makes the pages load quicker. About a month ago a similar comment was made by it - you can see it in the contributions history and the warning they received for it. Unfortunately, these sorts of inflammatory edit summaries are not routinely purged from the page history. Let me know if it happens again. Depending on the circumstances and timing, I can likely do more than leave a simple warning. --HappyCamper 04:38, 5 April 2007 (UTC)

[edit] Here's a Smile!

[edit] Article ratings, templates

Hi Paul - don't worry too much about the article ratings. Article tagging helps automated bots on Wikipedia to compile data on them. It also helps others who use special article categories as directories to look for interesting articles. Some Wikipedians really like numbers and statistics on articles. The WP:1.0 team also uses it to keep track of things. This is why you will sometimes see articles tagged en mass. It is generally expected that those more familiar with the subject will update the classifications, so feel free to change them as you see fit. Typically, a justification is not provided, although they are generally much appreciated. From an editorial point of view, this is not as high a priority as improving the articles themselves.

Also, if you want to link to a template without having it show up on a page, you can use the "template link" template: {{tl}}. For example, the {{inuse}} template is handy to have at time. You can also use link to it by adding a colon right before it: Template:Tl. This also works for categories. There is a directory of templates at Wikipedia:Template messages, but don't worry too much about needing to use the "right" template. If one is really needed, sooner or later a Wikipedian will come by and add it. --HappyCamper 21:12, 11 April 2007 (UTC)

[edit] Updates

I updated that list. Would you like to start an article on how to transform the 2D harmonic oscillator to the Morse oscillator? --HappyCamper 19:44, 15 April 2007 (UTC)

[edit] when reporting vandalism,

Please report it to WP:AIV instead of WP:ANI. AIV is a dedicated area for vandalism reports, and you'll get a much faster response there. — coel acan — 23:45, 18 April 2007 (UTC)

[edit] Just a suggestion

If you're reporting vandalism, you might want to try using TWINKLE ♥♥ ΜÏΠЄSΓRΘΠ€ ♥♥ ^{slurp me!} 08:15, 12 May 2007 (UTC)

[edit] Re:

I thought it was a vandalism so I reverted it, but then again I kind of realized the change might be made in good faith, so I reverted myself and I'll let the editors decide I guess. --Yamamoto Ichiro (山本一郎)(会話) 14:38, 16 May 2007 (UTC)

Btw, Japanese people usually are not good at English, so you might want to keep that in mind as well. I don't participate in content disputes, so I don't know how to deal with that edit. --Yamamoto Ichiro (山本一郎)(会話) 14:42, 16 May 2007 (UTC)

[edit] Jan Ligthart

Geachte heer Wormer (nu weet ik zeker dat u een man bent), dank voor uw adhaesie. Fijn te horen dat mijn NRC artikel dit effect gehad heeft. Ik denk niet dat die beide voordrachten uitgetypt gaan worden. Het zal veel gaan met slides, gespreksnotities en discussies. Maar wellicht dat ik van de zomer ertoe kom om de uitwerking van deze Jan Ligthart affaire op mijn denken over Wikipedia op papier te zetten. Vriendelijke groet,----Dolph Kohnstamm 14:41, 21 May 2007 (UTC)

Hieronder een bericht van Sander Spek die samen met mij deze voordrachten zal verzorgen. VRgr.--Dolph Kohnstamm 07:22, 23 May 2007 (UTC)

Als ik me even mag inmengen, P. Wormer is natuurlijk ook welkom op een van de lezingen. De Studium Generale-lezingen zijn op maandag 4 juni 's avonds op de UvA, en in het najaar een lunchsessie op de TU/e. Sander Spek (overleg) 23 mei 2007 08:18 (CEST)

[edit] Scripts

Just thought you might want to browse through this to improve your editing experience here. Cheers, --HappyCamper 03:37, 23 May 2007 (UTC)

Hmm...I think the script is working. Just experiment more, you're doing the right thing. --HappyCamper 13:25, 25 May 2007 (UTC)

Thanks for improving the article after the merging. Much appreciated! My gut feeling is that "spherical square well" is quite common, but I agree with you that it is confusing. I think it mixes ideas from two different coordinate systems. A square well feels more native in Cartesian coordinates, whereas a central potential is better understood in spherical coordinates. What you would recommend for its replacement? I cannot see this spherical square very well at all, but I sort of vaguely imagine a vacuum cleaner with an infinitely thin nozzle which vacuums with constant suction up to a fixed distance. Just quickly checking, I took a textbook off my shelf (Bransden & Joachain, 2nd Ed.) and it refers to the potential as the "three-dimensional spherically symmetric square well". Perhaps this is better. --HappyCamper 11:32, 26 May 2007 (UTC)

Hmm...you just contributed a curious operator identity. Where does it come from? I'd like to learn more. See ([2]). --HappyCamper 01:06, 28 May 2007 (UTC)

[edit] LCAO

Paul, I have responded on my talk page a couple of times today as I dug up material. --Bduke 08:09, 10 June 2007 (UTC)

[edit] Article restructuring

Brief note: I decided to split the hydrogen-like article into two and created 1s Slater-type function in the process. I left some messages on the article and user talk pages too. --HappyCamper 02:52, 12 June 2007 (UTC)

I wish that editor didn't decide to leave! Well, I guess I will have to try harder if he comes back: [3]...Anyway, I don't think this show/hide is particularly widespread on Wikipedia, but I think it would be good to experiment with it regardless. What is next on your to-do list apart from hydrogen-like atom? --HappyCamper 23:20, 12 June 2007 (UTC)

Hi HC, I noticed that you are interested in Lie groups, so the following will interest you. All degenerate states of the 3D isotropic harmonic oscillator span an irrep of U(3). This is because the 2nd quantized Hamiltonian is a Casimir of U(3). Because we are dealing with boson operators, the irrep is the one labeled by a Young diagram of one row and n boxes. Spherical harmonics span irreps of SO(3), so we see in our solution states adapted to the group chain U(3) - SU(3) - SO(3) - SO(2). This is a very well-known chain. All homogeneous polynomials in x, y and z of order n span the same (permutationally symmetric) irrep of U(3) as the 3D boson operators. When we factor out powers of r² from the polynomials, we make the subduction U(3) - SO(3). This factoring process is the one we use when we go from Cartesian GTOs to spherical GTOs. It is also applied when we make a Taylor expansion of the solution of the Laplace equation, there it has the consequence that only multipoles appear of which all (partial) traces vanish. I would like to drop this information somewhere in Wikipedia, but I don't where, do you have any suggestions?--P.wormer 09:04, 13 June 2007 (UTC)

Yes, you are quite right - this interests me immensely!! I don't know enough about these topics to judge, but perhaps we need new page on algebraic methods for quantum mechanics. What do you think? --HappyCamper 22:02, 13 June 2007 (UTC)

Or perhaps starting List of Casimir operators would be a good idea too. --HappyCamper 03:00, 15 June 2007 (UTC)

[edit] 3D harmonic oscillator

Thanks for your correction, it was my mistake. Dan Gluck 14:11, 12 June 2007 (UTC)

[edit] Argh!

I had such a good response written out for you - and just when I was about to click "save page", of all things, the power went out! So, this will have to suffice. In short, I agree with everything that you said, perhaps even your last note. I think we should have a section describing the "nuclei being significantly heavier" heuristic, but not more - I don't think people appreciate how nontrivial the approximation really is. Perhaps mentioning "adiabatic approximation" right at the top will be helpful, but there is no rush to implement any of these changes. Finally, forget about the anon - I'm not convinced they have any intention of following up with their concerns. If anything, keep an eye on the FC person! :-) --HappyCamper 19:44, 19 June 2007 (UTC)

[edit] Normalization constant

Hmm...I didn't think of double checking with Hydrogen-like atom. But, the expressions look the same to me though, except one uses reduced mass coordinates. Maybe I missed something? --HappyCamper 17:21, 25 June 2007 (UTC)

Ah, I see. Sorry about that - no, I copied this from B and J. I think that cube should be there, but I haven't worked out the details yet. I'm halfway done. --HappyCamper 17:30, 25 June 2007 (UTC)

They make use of this result (I haven't verified this yet): $\int^\infty_0 e^{-\rho} \rho^{2l} [L^{2l+1}_{n+l}(\rho)]^2 \rho^2 \, d\rho = \frac{2n[(n+l)!]^3}{(n-l-1)!}$ --HappyCamper 17:34, 25 June 2007 (UTC)

I'll keep this simple: you are the best!! --HappyCamper 17:12, 27 June 2007 (UTC)

[edit] Møller-Plesset

You have added some great material to the MP article. Well done. I do however have a slight disagreement. Your development is not wrong, but it is not what seems to me standard. Most texts (e.g. Introduction to Computational Chemistry, Frank Jensen) define the perturbation as simply H - F, and this gives MP0 as the sum of orbital energies and MP1 adds the correction to give the HF energy. You have defined the perturbation such that MP0 is is the HF energy and the first order correction zero. We also need to be clear about the difference between the energy to n'th order and the n'th order correction. Jensen for example gives:-

MP0 = E(MP0) = sum of orbital energies

MP1 = MP0 + E(MP1) = E(HF)

Which way should we go with this? --Bduke 23:37, 29 June 2007 (UTC)

Hi Paul, I have a few ideas about this but am rather tied up today to develop them at length. In the meantime, do you mind if we copy this section from your talk page and the one from mine to the MP article talk page, to encourage others to join in? --Bduke 23:15, 30 June 2007 (UTC)

This discussion copied to Talk:Møller-Plesset perturbation theory. --Bduke 08:08, 1 July 2007 (UTC)

[edit] Moment of Inertia

Thanks for your comments. My linear algebra textbook actually doesn't mention the term "unit matrix", and when I first edited this article the term led to a Wikipedia article which said that the unit matrix is one with every entry equal to one (that has since been changed). Also, I do know that eigenvalues can in general be both positive and negative; however, in this case they're positive (except for one axis of an ideal rod, but that's unrealistic). That edit had been bugging me, since I knew that positive definiteness was a sufficient but not necessary condition for diagonalizability. At the time of my edit I thought that being symmetric did not necessarily make a matrix diagonalizable, but after checking my textbook I see that it does. I've changed that sentence back to its previous state as a result. Anarchic Fox 09:47, 4 July 2007 (UTC)

[edit] Intermolecular forces and Laguerre

I think it's simpler this way: [4]. I could move the page to Laplace expansion (determinant), but then, the interwikilinks would need to be updated. Yes, and the Laguerres are different! --HappyCamper 16:17, 6 July 2007 (UTC)

[edit] Hilbert spaces

Alas I don't have access to j.chem.phys at the moment, and this issue of Hilbert spaces always confused me - forgive me if this question seems dim - Is the Hilbert space formed by the set of atomic orbitals of a hydrogen atom (Z=1) the same Hilbert space as that formed by the Z=2 hydrogenic atom? sbandrews (t) 07:56, 17 July 2007 (UTC)

A basis of hydrogen orbitals of whatever Z does not span any a Hilbert space (which by definition is complete in the sense that any Cauchy sequence converges to an element of the space). Hydrogen orbitals span only an (incomplete) subspace of the Hilbert space. To span the whole Hilbert space the continuous-energy (non-square integrable) functions must be included in the basis. This is because the bound state radial function varies as a function of n. However, a basis $r^{l} \exp(-\zeta r) Y_{lm}L^{2l+1}_{n-l-1}(r)\,$ with n, l and m running and ζ arbitrarily fixed is a complete basis for any square integrable function of x, y, and z. By complete I mean that the "distance" between the expanded function and its expansion can be made arbitrarily small (Parseval's equality). --P.wormer 08:15, 17 July 2007 (UTC)

So the problem is that the E>0 solutions of the hydrogen problem are not considored hydrogen orbitals. They would be scattered waves? - when combined with the bound state functions they together span the Hilbert space, is that correct? sbandrews (t) 09:04, 17 July 2007 (UTC)

Yes, an orbital is square integrable, the E>0 solutions are not square integrable and hence not orbitals. (The E>0 solutions are known as scattering states, and they are indeed the waves you find in proton-electron scattering). Yes, you need scattering states to span the whole Hilbert space. But their use is very awkward.--P.wormer 09:11, 17 July 2007 (UTC)

The Moller-Plesset article: Hello Paul,

  I was interested in your MP article and the conversations you and Brian Duke had.  I was wondering about mentioning Brillouin's Theorem and the lack of single excitations in the 2nd order energy corrections.  As to a Moller-Plesset theorem, I too have not run into this anywhere.

Gordon GallupGgallup 01:10, 1 September 2007 (UTC)

[edit] Liquefaction CO2

Hello Paul. I have no objections to someone else using my pictures, including Citizendium, its editors and readers, and you are free to use them within the widest limits allowed by the GFDL. However, the ability to contribute under a (traceable) pseudonym is a right that I am not willing to forfeit right now. Besides, I do believe that if some of my works can show their usefulness per se my real name needn't be attached to them, since it wouldn't add any value. I'm sorry if some Citizendium policies prevent you and others from taking benefit of other people's free works. Let me know if I can be of help with something else. Good luck, --BrokenArrow 20:40, 11 September 2007 (UTC)